It's a concrete that: 1) breaks down in water in a day(!), and 2) has a "5 times
higher impact on human health and 3 times higher impact on eco-toxicity as compared to concrete.".
I can't speak _specifically_ to ethanol, but there are good reasons for the US to provide various subsidies to farms. A visceral example -- if there is a large "world war III" and the US doesn't have a strong Agricultural sector, we could be screwed. It is worth keeping domestic agriculture strong, to hedge against the case where we can't buy produce from other countries. I suspect ethanol is a subset of this general approach. Worth noting I'm no expert, this is just my extremely layman understanding.
"It is important to note that biofuel production and consumption, in and of itself, will not reduce GHG or conventional pollutant emissions, lessen petroleum imports, or alleviate pressure on exhaustible resources."
Its only ridiculous if you view it as a subsidy for ethanol fuel rather than a subsidy for the corn industry. All the government is doing there is creating a market where one wouldn't otherwise exist.
Because the Iowa caucus is the first Presidential primary and it gets old gas cars off the road quicker by gunking up their fuel systems, allowing manufacturers to sell newer vehicles.
I mean the subsidies exist regardless of what the corn is used for and the rural folks are the most angry about ethanol in their fuel. I'm not sure this explanation lines up all the way.
Out in the country is the only place I can still find 100% gasoline.
The irony there is that most of the government subsidies and crop insurance programs come with stipulations related to how the crops are used. The last two years corn farmers in my area have had a hell if a time with drought. The corn ends up rotting in the field specifically because they can't claim insurance or get government assistance if they find another use for the corn, even if the other use only pays a fraction of what a full harvest would have yielded.
Nobody is willing to upset massive industrial farmers. Small farmers and homesteaders are regularly upset by the government.
If I want to sell you raw milk from a cow on my pasture it can only be for non-human consumption. If I want to sell you beef you either have to buy 1/4 or more of the animal before its processed or I have to load it onto a trailer and allow a state or USDA facility process it, leaving me with lovely packaged cuts that have a high level of stress hormones and was sprayed down with bleach.
I think this take is pretty funny because it's in instance where our elected officials are responding directly to the will of the votes that actually matter. Which is pretty refreshing compared to listening to the campaign donations that matter.
I want more of this kind of thing, not less. Politicians should be scared to piss lots of different voting blocs off. The way we do democracy is terrible at rewarding politicians for enacting (roughly) the will of the people.
Farmers are a tiny fraction of the voting population. Politicians are more concerned with farm lobbying money rather than the actual voters themselves.
I think this is off topic and I'm not the expert but it's a relatively reliable and established process that replaced lead in gasoline. I did some quick digging and didn't turn up any research of an alternative to ethanol for anti knock so perhaps this is why.
Ethanol free lead free gasoline works just fine. Some stations sell it. It just costs more because the ethanol is subsidized.
Cars don’t need ethanol. In fact they don’t like it. It causes problems for older cars, the auto industry had to adjust things to be able to survive a certain percent ethanol without damage.
Ethanol breaks down or degrades certain polymers (formerly) used in fuel systems. But in the actual engine, it's fine: it has lower energy content but a very high octane rating compared to other constituents of gasoline.
Sweet jesus was anything stupider than the solar roadways idea? "Let's take a technology that can easily be aggregated in appropriate, economies-of-scale implementations and _distribute them_ and require them to be extraordinarily more durable while running voltage through a surface that's being contacted by random people thousands of times a day, with the miles and miles of additional distributed infrastructure necessary to boot!"
Loads of things are stupider in that sense and actually done.
They're a bad fit in practice on basically every count, but the idea was interesting enough to pass the elevator pitch sniff test. Ruggidised PV as footpaths might not even suck, though I suspect even then they'd be better as roofing over footpaths rather underfoot.
My favorite part about the video was them talking about how much square footage roads take up and how that space could be used for solar panels, while showing footage of vast fields of open land right next to a road.
Given how often I still see people dunking on PV due to the land usage, I unironically think that's one of the better points.
Yes, I know there's plenty of better land, but comparing the scale needed to something we've already got likely helps change people's minds about the practicality of PV.
Alternatively, some other researcher can say “cool, some problems I can try to address with future work!”
Or it can go by the wayside. Both outcomes are fine. But no need to pre-emptively dismiss something that is obviously not being pitched as a production-ready building material…
This is much like staff.[1] Staff is a kind of cheap artificial stone, made from gypsum, cement, dextrin, and glycerin, with some long plant fibers for tensile strength. It was
used for temporary exhibition buildings for various fairs a century ago.
The Palace of Fine Arts colonnade in San Francisco, built for a 1915 fair, was originally made from staff. By the 1960s, it was a ruin. The current version is a full rebuild from 1974 in more durable materials.
There are more promising bio-materials for construction.
Attempts have been made to make boards from bagasse, the leftover fiber from sugar cane processing. It works, more or less. The most useful application for bagasse is making clamshell containers and plates for fast food. It's cheap, biodegradable, and non-toxic.
They're building tall buildings out of "wood" nowadays, but it's so processed, sliced up, layered and laminated, and pumped full of epoxies that it's really more down to aesthetics than any environmental benefit; that is, effort / energy investment is high to the point where it's probably cheaper to make steel, and they're not biodegradeable.
There’s still some environmental benefit; wood is so much lighter than concrete or metal as a rule, that you end up needing not only less material in general but also less material in the structure because the frame weighs less and needs less support, not to mention general carbon savings from transportation of heavy material.
It’s also a major time saver since unlike concrete it doesn’t need to set, and the products are basically manufactured panels that don’t need specialized workers to install.
Sometimes I wonder if buildings really should last hundreds of years taking up that space. Similar to how laws last almost forever and lead to byzantine requirements and tricky interpretations.
Would be interesting if transient infrastructure and time-limited laws would lead to a more beneficial way of living.
Japanese buildings are designed to last about 50 years iirc, after which they're demolished. Temples are rebuilt every X years as well. The building materials, at least in those temples, are mostly natural (wood, mostly cleverly jointed so minimal metal required). IDK if they're still popular but the tatami mat is made out of rice straw, also fully biodegradeable (assuming the stitching isn't plastic).
If buildings could be more easily repurposed this wouldn't even really be a question that needs to be asked. Throughout most of human history larger buildings were repurposed instead of being destroyed, because there wasn't an illusion of limitless materials and labour. The proliferation of specialized buildings after the late 1800s because of that illusion rising, especially for commercial interests, is one half of a problem. The other being regulations written for those specialized buildings that provide little or no possibility of being repurposed.
For example old roadside motels from the '50s and '60s could easily be remade into dorm style apartments with micro kitchens supplemented by communal bathrooms, but laws, especially hygiene and fire codes, currently prevent that. Those motels are built of sturdier materials than many modern homes, and only need to be refitted with fire suppression systems and heat pumps to be cheap housing.
Making temporary housing is just creating a new problem rather than solving an existing one.
I really wasn’t focusing on the USA and its red-tape zoning and refurb laws. For example in the EU, lots of cities have 1-3 city halls at this point. The older ones are often repurposed into government offices or museums.
But what if they disappeared entirely and we built something new in its place? What if the entire block was completely transformed at some point?
Well, that happened with some European cities as a result of WW2.
I remember a celebration in the late 1980s for a retiring British architect/art historian, who reminisced about being an architecture student during the Blitz in London. While he and his pals sheltered underground during the bombing, they shared a (slightly shameful) excitement about the prospect of rebuilding London with "something new" after the war was over.
In contrast to some European cities, where the goal was to recreate as much of the pre-war architecture as possible, postwar London was, as I understand it, rebuilt with lots of new architecture. My impression is that most people think a lot of it was pretty terrible.
The question then becomes how do you make a building degrade in a way that isn't dangerous to the occupants? When a building does degrade, it takes more energy to remove the debris and build a new structure. Can that be minimized as well? This isn't to say I'm against the idea, just thinking out loud
There has been another thread on HN, with a research starting from this, which has developed a concrete suitable for use on Moon or on Mars, where there is no danger of it being broken down by water and where its production would be simplified by this choice, because starch must be produced anyway for food, so making concrete does not require additional production facilities.
Interesting. The degradation in wet conditions seems like a major challenge to solve.
I initially was skeptical of the utility when I saw the mention of heating requirements, but the temperatures aren’t that extreme, and seem very reasonably achieved with electrified energy sources (which in turn can easily be supplied via renewables).
Being able to produce concrete without the emissions involved with the production of portland cement is a major goal of decarbonizing the building stock, so it’s always good to see new lines of research in this front, even if still in the germinal stages!
ARPA-E Hestia has some cool alternatives (a bit further along in research stages) for those interested:
> Being able to produce concrete without the emissions involved with the production of portland cement is a major goal of decarbonizing the building stock
AFAICT, cornstarch has a similar emissions to portland cement:
A big possible issue with this is that cornstarch (at least the way it's currently produced) has the same carbon footprint as portland cement, which it replaces in this process.
The authors do mention approximately equivalent carbon footprints in their LCA, but they don’t really explain how they account for the energy involved in heating the corncrete. If they are assuming a clean grid or renewable source already, then there’s not much potential for reducing that carbon footprint. But if they are assuming a typical or dirty grid, then that’s one area where the footprint can come down a significant amount. I was only skimming but I didn’t see a mention of what assumption they used there.
> But if they are assuming a typical or dirty grid, then that’s one area where the footprint can come down a significant amount.
Not sure I understand how, since regular concrete made from portland cement does require heating to cure - in fact it's exothermic.
The vast majority of the emissions from traditional concrete come from the manufacturing of portland cement. It's not clear how a renewable grid would significantly lower the emissions of producing cornstarch, since the majority of emissions happen at the agricultural stage, via the petroleum based fertilizers.
Corn-based electrical insulators proved problematic in cars due to rodents eating the tasty insulators. Something to check in testing this material.
Mycelium based construction materials may be more beneficial due to fire resistance, insulation and excellent R values and relative unpalatability. Ecovative is a good place to learn about this (no personal affiliations, just a fan.)
Well, tbf the paper clearly says it was published in 2017 and the first author is the same person who uploaded the presumably experimental stage video to YouTube in 2015.
in concrete, cement makes up less than 25% of the mix, and here corn is like 20%, so I think when you're comparing this class of materials (concrete, epoxy granite, concrete), it makes sense to describe in terms of the binder even if it is a smaller % of the complete product.
We have enough food to feed something like an extra 1.5 billion people.
Fixing waste and distribution would more than make up for it, and that’s not including the possibility of shifting corn over from ethanol instead if this proves actually useful.
Does the polymerization prevent biodegradation (e.g. digestion by fungus)
I don't think I have access to the full paper, but it is described as biodegradable, which seems to be the opposite of what you'd want your house to be made of?
Siliation or esterization of the long carbohydrate chains would make them close to indigestible, and also far more water-resistant, but at that point the cost (including environmental) would outweigh the benefits over concrete.
> Under water submerged conditions (20˚C), hardened CoRncrete specimens showed partial to complete degradation within a day.
While this certainly isn't great for most obvious building use-cases, I wonder if it would have utility for ex. building a research base on the moon someday.
I actually have some friends working on construction materials for moon bases! ie turning regolith into bricks, using drones/robots to assemble the structures etc. pretty cool stuff. There’s a fair bit of research going on into this problem.
I think the main challenge with your idea is that you have to get the corn starch to the moon… you really want your solution to be focused on ISRU (in-situ research utilization) as much as possible.
Portland cement is not easily replaceable in its main use (building construction) because concrete made with organic substances as sand grain binders, be it cornstarch or epoxy-polymer, isn't fire resistant.
The compressive strength of cornstarch concrete maxes out at 26 MPa according to the paper, while different Portland cement formulations range from 20-50 MPa, and epoxy-polymer can go up to > 100 MPa, though brittleness is a problem.
The optimal strategy for cleaning up Portland cement production is probably (1) renewable-based electrification of the kilns used to make CaO from CaCO3 (limestone), and (2) capture and stabilization of the CO2 from the kilns in a form like carbon fiber or diamond. Still a bit sci-fi but technologically feasible (but not economical at present).
Another major area for decarbonization is also just better design - just by making it easier to fabricate and deploy shaped beams/floor systems which allocate material in a way that mildly follows the moment diagram, you can knock out massive amounts of emissions, just by virtue of the fact that the developing world will largely be building all floor systems out of concrete…
I'm gonna guess it's more likely that it won't last as a building material, rather than believe no one thought to mix sand, cornstarch and water until now..
Unclear on that first point. The authors claim 26 MPa for CoRncrete, which is about the same as the higher end of the range of concrete (~28 MPa) but much cheaper. On the other hand, it sounds like the paper's saying it's also much less durable.
I wouldn't count anything under 40 MPA as "high strength concrete" at all. Thats where high strength concrete starts for me. High strength concrete mixes can go up to 180-200 MPA although thats some crazy specialty stuff for very niche uses.
25 mpa concrete is "i'm doing my driveway" concrete or "I bought a bag at home depot" concrete not high strength concrete.
And of course, cornstarch is only about 70% of the weight of corn. IIRC grain production statistics are usually by dry weight, but if we assume wet weight, it's even worse. Even if we completely obliterated the meat and biofuel industries worldwide, we would struggle to meet a quarter of the current demand for cement, which anyway is forecast to increase.
Recalling when, after years of hype, the demand for corn-based ethanol as a fuel competed with corn for food, leading to even greater food insecurity world-wide.
Grifter's gotta grift, but that doesn't mean their BS gets to go unchallenged.
Interesting, just watched a guy that turned cooking oils into plastic (with a catalyst like iron). And he got into how canola oil, was a rebranded industrial lubricant that needed a new market post wwII. (just with lowered toxicity levels)
And earlier listened to Robert Kennedy on a podcast where he discussed how offshore wind farms, have turbines placed in the ocean with giant blades that can explode and pollute water with shards that close beaches and kill Whales. While significantly more expensive than terrestrial wind farms.
Public opinion is often swayed by such labels like "environmentally friendly", "reusable", "pro environment". Who could not support such things ...
Turns out environmentally friendly products, often are just a swindle to get massive amount of subsidy money from government ... for bad ideas.
It's a form of corruption, as politicians that approve these things often benefit in some way. While public loses.
It's a concrete that: 1) breaks down in water in a day(!), and 2) has a "5 times higher impact on human health and 3 times higher impact on eco-toxicity as compared to concrete.".
Cool research, but I'll pass on using it.
Having 'negative' results like this published is so good though because then it's harder to scam people with this idea in the future.
Why do we still use corn based ethanol?
I can't speak _specifically_ to ethanol, but there are good reasons for the US to provide various subsidies to farms. A visceral example -- if there is a large "world war III" and the US doesn't have a strong Agricultural sector, we could be screwed. It is worth keeping domestic agriculture strong, to hedge against the case where we can't buy produce from other countries. I suspect ethanol is a subset of this general approach. Worth noting I'm no expert, this is just my extremely layman understanding.
some more discussion on this here: https://en.wikipedia.org/wiki/Agricultural_policy_of_the_Uni...
As far as i know, ethanol and all biofuels are/were a dead end. They were used purely for farmer subsidies and the energy independence was an excuse.
Trust the government and their experts though.
Literally a report from government experts:
"It is important to note that biofuel production and consumption, in and of itself, will not reduce GHG or conventional pollutant emissions, lessen petroleum imports, or alleviate pressure on exhaustible resources."
Which makes it even more ridiculous that governments subsidize ethanol for fuel.
Its only ridiculous if you view it as a subsidy for ethanol fuel rather than a subsidy for the corn industry. All the government is doing there is creating a market where one wouldn't otherwise exist.
what is the source?
Googling the exact quote: https://www.epa.gov/environmental-economics/economics-biofue...
Because the Iowa caucus is the first Presidential primary and it gets old gas cars off the road quicker by gunking up their fuel systems, allowing manufacturers to sell newer vehicles.
I don’t think any gas engine built in the last twenty to thirty years has problems with 10% ethanol.
Agreed. How many any automobiles older than that are not already in need of new hoses and gaskets?
I mean the subsidies exist regardless of what the corn is used for and the rural folks are the most angry about ethanol in their fuel. I'm not sure this explanation lines up all the way.
Out in the country is the only place I can still find 100% gasoline.
It’s a lot harder to justify subsidies if the corn was just rotting in the field.
But mandating a certain percentage of ethanol ensures a minimum level of demand, preventing that problem.
The irony there is that most of the government subsidies and crop insurance programs come with stipulations related to how the crops are used. The last two years corn farmers in my area have had a hell if a time with drought. The corn ends up rotting in the field specifically because they can't claim insurance or get government assistance if they find another use for the corn, even if the other use only pays a fraction of what a full harvest would have yielded.
Nobody is willing to upset farmers.
Nobody is willing to upset massive industrial farmers. Small farmers and homesteaders are regularly upset by the government.
If I want to sell you raw milk from a cow on my pasture it can only be for non-human consumption. If I want to sell you beef you either have to buy 1/4 or more of the animal before its processed or I have to load it onto a trailer and allow a state or USDA facility process it, leaving me with lovely packaged cuts that have a high level of stress hormones and was sprayed down with bleach.
I think this take is pretty funny because it's in instance where our elected officials are responding directly to the will of the votes that actually matter. Which is pretty refreshing compared to listening to the campaign donations that matter.
I want more of this kind of thing, not less. Politicians should be scared to piss lots of different voting blocs off. The way we do democracy is terrible at rewarding politicians for enacting (roughly) the will of the people.
Farmers are a tiny fraction of the voting population. Politicians are more concerned with farm lobbying money rather than the actual voters themselves.
The votes that matter?
Or big agribusiness and their campaign donations?
I think this is off topic and I'm not the expert but it's a relatively reliable and established process that replaced lead in gasoline. I did some quick digging and didn't turn up any research of an alternative to ethanol for anti knock so perhaps this is why.
Ethanol free lead free gasoline works just fine. Some stations sell it. It just costs more because the ethanol is subsidized.
Cars don’t need ethanol. In fact they don’t like it. It causes problems for older cars, the auto industry had to adjust things to be able to survive a certain percent ethanol without damage.
Ethanol breaks down or degrades certain polymers (formerly) used in fuel systems. But in the actual engine, it's fine: it has lower energy content but a very high octane rating compared to other constituents of gasoline.
Yeah when the CORN-FREAKING-CRETE skyscraper crowd funding video comes out we can all be more skeptical than we were for SOLAR-FREAKING-ROADWAYS.
Sweet jesus was anything stupider than the solar roadways idea? "Let's take a technology that can easily be aggregated in appropriate, economies-of-scale implementations and _distribute them_ and require them to be extraordinarily more durable while running voltage through a surface that's being contacted by random people thousands of times a day, with the miles and miles of additional distributed infrastructure necessary to boot!"
Loads of things are stupider in that sense and actually done.
They're a bad fit in practice on basically every count, but the idea was interesting enough to pass the elevator pitch sniff test. Ruggidised PV as footpaths might not even suck, though I suspect even then they'd be better as roofing over footpaths rather underfoot.
My favorite part about the video was them talking about how much square footage roads take up and how that space could be used for solar panels, while showing footage of vast fields of open land right next to a road.
Given how often I still see people dunking on PV due to the land usage, I unironically think that's one of the better points.
Yes, I know there's plenty of better land, but comparing the scale needed to something we've already got likely helps change people's minds about the practicality of PV.
Alternatively, some other researcher can say “cool, some problems I can try to address with future work!”
Or it can go by the wayside. Both outcomes are fine. But no need to pre-emptively dismiss something that is obviously not being pitched as a production-ready building material…
This is much like staff.[1] Staff is a kind of cheap artificial stone, made from gypsum, cement, dextrin, and glycerin, with some long plant fibers for tensile strength. It was used for temporary exhibition buildings for various fairs a century ago. The Palace of Fine Arts colonnade in San Francisco, built for a 1915 fair, was originally made from staff. By the 1960s, it was a ruin. The current version is a full rebuild from 1974 in more durable materials.
There are more promising bio-materials for construction.
Attempts have been made to make boards from bagasse, the leftover fiber from sugar cane processing. It works, more or less. The most useful application for bagasse is making clamshell containers and plates for fast food. It's cheap, biodegradable, and non-toxic.
[1] https://en.wikipedia.org/wiki/Staff_(building_material)
They're building tall buildings out of "wood" nowadays, but it's so processed, sliced up, layered and laminated, and pumped full of epoxies that it's really more down to aesthetics than any environmental benefit; that is, effort / energy investment is high to the point where it's probably cheaper to make steel, and they're not biodegradeable.
There’s still some environmental benefit; wood is so much lighter than concrete or metal as a rule, that you end up needing not only less material in general but also less material in the structure because the frame weighs less and needs less support, not to mention general carbon savings from transportation of heavy material.
It’s also a major time saver since unlike concrete it doesn’t need to set, and the products are basically manufactured panels that don’t need specialized workers to install.
That seems rather long-lasting for a temporary building. I wonder what other buildings should be temporary?
> That seems rather long-lasting for a temporary building.
By 1964, not much of the colonnade was still standing. This was all that was left.[1] What you see today is a full rebuild.
[1] https://www.sfgate.com/bayarea/article/Dramatic-Palace-of-Fi...
Sometimes I wonder if buildings really should last hundreds of years taking up that space. Similar to how laws last almost forever and lead to byzantine requirements and tricky interpretations.
Would be interesting if transient infrastructure and time-limited laws would lead to a more beneficial way of living.
Japanese buildings are designed to last about 50 years iirc, after which they're demolished. Temples are rebuilt every X years as well. The building materials, at least in those temples, are mostly natural (wood, mostly cleverly jointed so minimal metal required). IDK if they're still popular but the tatami mat is made out of rice straw, also fully biodegradeable (assuming the stitching isn't plastic).
AFAIK clever wood joinery is so niche nowadays that it’s really hard to find people who can still build like that.
Japan is not in the same era as what you're describing.
There are many modern buildings that are built the same way as other modern cities and designed to last.
They have very modern infrastructure, and while what you're describing does exist, but is by no means the norm nowadays.
If buildings could be more easily repurposed this wouldn't even really be a question that needs to be asked. Throughout most of human history larger buildings were repurposed instead of being destroyed, because there wasn't an illusion of limitless materials and labour. The proliferation of specialized buildings after the late 1800s because of that illusion rising, especially for commercial interests, is one half of a problem. The other being regulations written for those specialized buildings that provide little or no possibility of being repurposed.
For example old roadside motels from the '50s and '60s could easily be remade into dorm style apartments with micro kitchens supplemented by communal bathrooms, but laws, especially hygiene and fire codes, currently prevent that. Those motels are built of sturdier materials than many modern homes, and only need to be refitted with fire suppression systems and heat pumps to be cheap housing.
Making temporary housing is just creating a new problem rather than solving an existing one.
I really wasn’t focusing on the USA and its red-tape zoning and refurb laws. For example in the EU, lots of cities have 1-3 city halls at this point. The older ones are often repurposed into government offices or museums.
But what if they disappeared entirely and we built something new in its place? What if the entire block was completely transformed at some point?
Well, that happened with some European cities as a result of WW2.
I remember a celebration in the late 1980s for a retiring British architect/art historian, who reminisced about being an architecture student during the Blitz in London. While he and his pals sheltered underground during the bombing, they shared a (slightly shameful) excitement about the prospect of rebuilding London with "something new" after the war was over.
In contrast to some European cities, where the goal was to recreate as much of the pre-war architecture as possible, postwar London was, as I understand it, rebuilt with lots of new architecture. My impression is that most people think a lot of it was pretty terrible.
The question then becomes how do you make a building degrade in a way that isn't dangerous to the occupants? When a building does degrade, it takes more energy to remove the debris and build a new structure. Can that be minimized as well? This isn't to say I'm against the idea, just thinking out loud
I was thinking less about potential energy usage / emissions, so that’s a good point. Probably solvable like the sibling comment about Japan.
I was philosophizing more about changing the way we enforce permanency of decisions taken by humans who lived before on everyone who comes after them.
No, just slums.
Thanks for contributing nothing of importance to the discussion on this thread.
There has been another thread on HN, with a research starting from this, which has developed a concrete suitable for use on Moon or on Mars, where there is no danger of it being broken down by water and where its production would be simplified by this choice, because starch must be produced anyway for food, so making concrete does not require additional production facilities.
https://news.ycombinator.com/item?id=41751122
Therefore even research results that do not seem useful in normal conditions may find some circumstances where their use becomes preferable.
Interesting. The degradation in wet conditions seems like a major challenge to solve.
I initially was skeptical of the utility when I saw the mention of heating requirements, but the temperatures aren’t that extreme, and seem very reasonably achieved with electrified energy sources (which in turn can easily be supplied via renewables).
Being able to produce concrete without the emissions involved with the production of portland cement is a major goal of decarbonizing the building stock, so it’s always good to see new lines of research in this front, even if still in the germinal stages!
ARPA-E Hestia has some cool alternatives (a bit further along in research stages) for those interested:
https://arpa-e.energy.gov/technologies/programs/hestia
> Being able to produce concrete without the emissions involved with the production of portland cement is a major goal of decarbonizing the building stock
AFAICT, cornstarch has a similar emissions to portland cement:
https://apps.carboncloud.com/climatehub/product-reports/id/7...
Yep, the authors do a relatively straightforward LCA and estimate essentially equally carbon footprint between concrete and “corncrete.”
Point still stands - it’s a major goal of building technology to mitigate the embodied carbon of buildings due to concrete.
Won’t that compete with food production?
A big possible issue with this is that cornstarch (at least the way it's currently produced) has the same carbon footprint as portland cement, which it replaces in this process.
https://apps.carboncloud.com/climatehub/product-reports/id/7....
The authors do mention approximately equivalent carbon footprints in their LCA, but they don’t really explain how they account for the energy involved in heating the corncrete. If they are assuming a clean grid or renewable source already, then there’s not much potential for reducing that carbon footprint. But if they are assuming a typical or dirty grid, then that’s one area where the footprint can come down a significant amount. I was only skimming but I didn’t see a mention of what assumption they used there.
> But if they are assuming a typical or dirty grid, then that’s one area where the footprint can come down a significant amount.
Not sure I understand how, since regular concrete made from portland cement does require heating to cure - in fact it's exothermic.
The vast majority of the emissions from traditional concrete come from the manufacturing of portland cement. It's not clear how a renewable grid would significantly lower the emissions of producing cornstarch, since the majority of emissions happen at the agricultural stage, via the petroleum based fertilizers.
Oops typo, corrected:
"regular concrete made from portland cement doesn't require heating to cure"
Corn-based electrical insulators proved problematic in cars due to rodents eating the tasty insulators. Something to check in testing this material. Mycelium based construction materials may be more beneficial due to fire resistance, insulation and excellent R values and relative unpalatability. Ecovative is a good place to learn about this (no personal affiliations, just a fan.)
This has been out for quite a while, there's even a YouTube video from 2015 showing how to make it using a microwave.
https://www.youtube.com/watch?v=b7dYcJaCOMU
Well, tbf the paper clearly says it was published in 2017 and the first author is the same person who uploaded the presumably experimental stage video to YouTube in 2015.
They mix 225g sand with 50g of corn starch.
It's more "sand based" than "corn based".
in concrete, cement makes up less than 25% of the mix, and here corn is like 20%, so I think when you're comparing this class of materials (concrete, epoxy granite, concrete), it makes sense to describe in terms of the binder even if it is a smaller % of the complete product.
All concrete is more aggregate than binder… but it’s the binder that matters from an emissions perspective.
Stop using food for anything else than food, people. We don't have enough arable land to waste on this stuff.
We have enough food to feed something like an extra 1.5 billion people.
Fixing waste and distribution would more than make up for it, and that’s not including the possibility of shifting corn over from ethanol instead if this proves actually useful.
Does the polymerization prevent biodegradation (e.g. digestion by fungus)
I don't think I have access to the full paper, but it is described as biodegradable, which seems to be the opposite of what you'd want your house to be made of?
Siliation or esterization of the long carbohydrate chains would make them close to indigestible, and also far more water-resistant, but at that point the cost (including environmental) would outweigh the benefits over concrete.
> Under water submerged conditions (20˚C), hardened CoRncrete specimens showed partial to complete degradation within a day.
While this certainly isn't great for most obvious building use-cases, I wonder if it would have utility for ex. building a research base on the moon someday.
I actually have some friends working on construction materials for moon bases! ie turning regolith into bricks, using drones/robots to assemble the structures etc. pretty cool stuff. There’s a fair bit of research going on into this problem.
I think the main challenge with your idea is that you have to get the corn starch to the moon… you really want your solution to be focused on ISRU (in-situ research utilization) as much as possible.
It's a 1:5 ratio starch:regolith
I think you'll find that transporting the water is far more costly, which would be the case with any lunar concrete
There is water on the moon. Not a lot, but there is some ice in deep craters at the poles. But there's no cornstarch.
Makes sense!
Full article here: https://www.sciencedirect.com/science/article/abs/pii/S09500...
Portland cement is not easily replaceable in its main use (building construction) because concrete made with organic substances as sand grain binders, be it cornstarch or epoxy-polymer, isn't fire resistant.
The compressive strength of cornstarch concrete maxes out at 26 MPa according to the paper, while different Portland cement formulations range from 20-50 MPa, and epoxy-polymer can go up to > 100 MPa, though brittleness is a problem.
The optimal strategy for cleaning up Portland cement production is probably (1) renewable-based electrification of the kilns used to make CaO from CaCO3 (limestone), and (2) capture and stabilization of the CO2 from the kilns in a form like carbon fiber or diamond. Still a bit sci-fi but technologically feasible (but not economical at present).
Another major area for decarbonization is also just better design - just by making it easier to fabricate and deploy shaped beams/floor systems which allocate material in a way that mildly follows the moment diagram, you can knock out massive amounts of emissions, just by virtue of the fact that the developing world will largely be building all floor systems out of concrete…
https://doi.org/10.1016/j.engstruct.2021.112955
HN meta: an actual research paper vs product posing as science. Nice.
I'm gonna guess it's more likely that it won't last as a building material, rather than believe no one thought to mix sand, cornstarch and water until now..
This is a thing not because it adds strength or sustainability. We produce way too much corn and they are looking for ways to use them up.
Unclear on that first point. The authors claim 26 MPa for CoRncrete, which is about the same as the higher end of the range of concrete (~28 MPa) but much cheaper. On the other hand, it sounds like the paper's saying it's also much less durable.
I wouldn't count anything under 40 MPA as "high strength concrete" at all. Thats where high strength concrete starts for me. High strength concrete mixes can go up to 180-200 MPA although thats some crazy specialty stuff for very niche uses.
25 mpa concrete is "i'm doing my driveway" concrete or "I bought a bag at home depot" concrete not high strength concrete.
Producing less corn rather than subsidizing it is the better way to go.
This just seems like another fake-green boondoggle, similar to ethanol.
Do ants eat it? They eat some corn-based insulation I have.
Topsoil is very limited, this seems like a bad idea.
please, let it be the registed commertial name. I would be awsome.
How does it handle water?
Perhaps they have to seal it so water doesn't get in.
(2017)
Before you get too excited:
- Global production of corn: 1.2 gigatonnes, source https://ipad.fas.usda.gov/cropexplorer/cropview/commodityVie...
- Global production of Portland cement: 4.1 gigatonnes, source https://gccassociation.org/key-facts/
And of course, cornstarch is only about 70% of the weight of corn. IIRC grain production statistics are usually by dry weight, but if we assume wet weight, it's even worse. Even if we completely obliterated the meat and biofuel industries worldwide, we would struggle to meet a quarter of the current demand for cement, which anyway is forecast to increase.
Here's hoping that corncrete doesn't interfere with all of that wonderful ethanol. /s
Encouraged to see the skepticism here.
Recalling when, after years of hype, the demand for corn-based ethanol as a fuel competed with corn for food, leading to even greater food insecurity world-wide.
Grifter's gotta grift, but that doesn't mean their BS gets to go unchallenged.
Ohio has entered the chat
Interesting, just watched a guy that turned cooking oils into plastic (with a catalyst like iron). And he got into how canola oil, was a rebranded industrial lubricant that needed a new market post wwII. (just with lowered toxicity levels)
"Seed Oil converts to PLASTIC"
https://www.youtube.com/watch?v=Ra_tCL5-4c0&t=1s
And earlier listened to Robert Kennedy on a podcast where he discussed how offshore wind farms, have turbines placed in the ocean with giant blades that can explode and pollute water with shards that close beaches and kill Whales. While significantly more expensive than terrestrial wind farms.
Public opinion is often swayed by such labels like "environmentally friendly", "reusable", "pro environment". Who could not support such things ... Turns out environmentally friendly products, often are just a swindle to get massive amount of subsidy money from government ... for bad ideas. It's a form of corruption, as politicians that approve these things often benefit in some way. While public loses.